Friday, December 12, 2008

What's a Model?

a simplified representation of a system or phenomenon, as in the sciences or economics, with any hypotheses required to describe the system or explain the phenomenon, often mathematically.

Got it? For example, I think of physics as a model of certain physical phenomena. Some decades ago, I often described a model as something used instead of something else, which replicates the important aspects of that “something else” for your purposes. Point being, that whether “A” is a good model of “B” depends on your objectives. One of my favorite examples was mannequins. For a tailor, a mannequin is a very good model of a young lady. In some ways, mannequins might even be better than the real thing – they don’t get tired, it doesn't hurt when you stick them with a pin, etc. However, as a thirty-something year old man, I found them a totally inadequate substitute for my purposes.

Often, mathematical models allow you to analyze the behavior of whatever you are modeling in ways that would be impractical in real life. For instance, with the proper model, you could model how a plane would behave in a crash and save yourself the expense of actually crashing planes. Closer to home, a budget is a model of your finances. So, you could examine how buying that Porsche you saw the other day would affect your finances without actually spending the money. Better to find out on paper that buying it is a bad idea than having to learn the hard way.

Models are very useful tools for analysis and planning, two things that I enjoy doing, and building them is an exercise in design (which I enjoy as well). Modeling ties three of my passions together.

Anyway, this is just a heads up that I will be posting models from time to time. For a very simple example, see the stock market spreadsheet referenced in one of my earlier posts.

p.s. For those readers who have been wondering why I haven’t posted in over three weeks, it’s because I’ve been hard at work developing a model that I will be posting soon.